Grinding machine



Jan. 29, 1.924. 1,482,294

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Jan. 29 1924. I W. F. FRASER GRINDING MACHINE Filedsept. 1a. 1919 e Sheets-Sheet 4,

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Jan. 29, 1924.

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Inventor. Warren F. Fv e r Aflvs.

Jan. 29 1924. 1,482,294

v W. F. FRASER GRINDING MACHINE Filed Sept. 18, 1919 6 Sheets-Sheet 6 Fig.8;

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Patented Jan. 29, 1924.,

GRINDING MACHINE.

Application filed September 18, 1919. Serial No. 324,349.

To all whom it may concern:

Be it known that I, WARREN F. FRASER, a citizen of the United States, and resident of Westboro, county of Worcester, State of Massachusetts, have invented an Improvement in Grinding Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts. I

This invention relates to improvements in grindingmachines and asillustrated herein is embodied in a machine for grinding curved surfaces such as'the surfaces of lenses and the like but it will be understood that the invention may be employed for the purpose of grinding or p olishin any kind of surface to which it is applicab e.

One of the objectsof the invention is to provide a grinding machine having a work supporting member and a work carrying member withmeans for producing a relative grinding movement between said members by means of which any effective point upon the grinding tool will traverse a more extended path during its cycle of movement than in machinesheretofore constructed.

This is accomplished in the preferred embodiment of the invention disclosed herein by causing one of the co-operating members to move in acurvilinear path, preferably a circular path, while the other member is moved in the path which is a resultant of a plurality of rectilinear movements in paths disposed in angular relation to each other.

Another object ofthe invention is to provide a grinding machine comprising a plurality of grinding niembersortools and a the Work carrylng member or members and the grinding member or members with means for releasing said pressure applying means whereby the co-operating work carrying member or members maybe separated to permit the insertion and removal of the work and the application of grinding or polishing material.

A further object of the invention is to provide driving mechanism for a machine of the Character above described which will enable a smooth and easy stopping and starting motion-of the relatively movable grinding and work carrying members.

A further object of the invention is to provide manually operable means preferably including a treadle for controlling the driving mechanism, means also being provided which may be operated fromsaid manually operable means for releasing the pressure between the work carrying member and its co-operating grinding member when the driving mechanism has been released from driving relation.

Other objects and features ofvthe inven tion includin improvements in special mechanisms Wlll more fully appear from the following descriptionand the accompanying drawings and will be pointed out in the annexed claims.

The drawings illustrate a preferred embodiment of my invention as applied to a lense grinding machine comprising a plurality of work carrying members and a co-operating plurality of grinding tools having surfaces formed to effect the proper grinding of curved or fiat surfaces, in which the grinding action is produced by abrasive or polishing material applied to the surface of the grindingtool.

In the drawings:

Fig. 1 is a front elevation of a machine embodying my invention, illustrationof the driving motor being omitted,

Fig. 2 is an end elevation of a machine illustrating particularly the driving mechanism, E

-Fig. 3 is an elevation "of the opposite end of the machine showing the means for releasing the pressure applying mechanism.

Fig. 4 is a view partly in vertical section and partly in elevation showing particularly the mechanism for producing relativegrinding movement between the work carrying members and the grinding members or tools,

Fig. 5 is a view mainly in vertical section on lines 5-5 Fig. 4,

Fig. 6 is a detail plan View showing the means for transmitting movement to the carriage for the grinding tools,

Fig. 7 is a detail vertical sectional view on lines 7-7, Fig. 6, Y

Fig. 8 is a plan view of a machine,

F ig. 9 is a detail elevation of the work carrying means, its support and means for producing pressure upon the same to force the work carrying means toward the grindin tool,

Fig. 10 is a detail sectional view on lines 1010 Fig. 4, illustrating the connection between the slide which supports the tool carriage and its driving mechanism, and,

Fig. 11 is a detail sectional view on lines 11'-11', Fig. 4, showing one of the eccentrics which operate the supports for the work carrying members.

i In grinding machines of the type to which the present invention relates it is desirable that each effective point upon the grinding tool which carries the abrasive shall traverse an'ext'ended path upon the work which lie "said-point shall not retrace any substantial portion thereof. It is also desirable that the successive, substantially parallel, portions of the path of each effective grinding point shall be quite widely spaced apart and that before completing its cycle of operation each grinding point shall traverse all of the surface intermediate of the lines previously traced by it. Otherwise the shifting of the abrasive during the grinding operation may cause regrinding of a previously traced line thus producing ascratch or uneven surface.

In the present invention this is acco1n- 'p'lished by causing the work carrying member or members to move in a curvilinear, preferably circular path and the grinding tool to move in a difier'entpath which preferablyis the resultant of two or more rec- 'tilinear movementsat an angle, desirably a right angle, to each other by producing rectilinear movements at. different rates of speed each of which differs from the other and from the movement of the work carry ing members, cycles of movement may he produced in which the paths described byv the various points upon the grinding tool r'iay be so related that every portion "of the work will be properly treated and a surface produced whichis free from scratches or other defects which would interfere with the proper refraction or reflection of the sur face treated.

'By providing means which will exert a constant 'yielding pressure between the work carrying member or members and the grinding too-1' or tools, auniform grinding operation is insured, and by employing means by which the pressure maybe released so that any or all of the co-operating workcarryingmembers and grinding tools may be separated a convenientinachine is produced in which the workman'may attend to the grinding of several ler'iseswith substantially the same facility as with a machine and at different speeds.

having a single pair of instrumentalities. Consequently the production of a skilled operator may be greatly increased.

Other features of the invention, such as the capability of the employment of a 'treadle mechanism adapted normally to permit the driving of the machineor which may be operated to release the driving mechanism and by further movement to release the pressure applying mechanism, still further aid in the saving of time of the operator, while enabling him to employboth hands in the insertion and removal of the work and its necessary manipulation during the process of manufacture.

The machine illustrated in the accompanying drawing comprises a base 1 upon which is mounted a supporting frame 2 for the driving mechanism and a superstructure consisting of bases 3' and upstanding posts 4 having at their upper ends journals 5 for the vertical shafts whichwactuate the support for the work carrying member or memers.

In the construction illustrated in the accompanying drawing a series of four work carrying members and four complementary Work carrying tools are employed, the work carrying members being given a circular movement while the work carrying tools are. given a movement which is the resultant of two independent movements ofaeach other It will however, be understood, that'so far as the present invention is concerned it is immaterial whether the work carrying members are given a circular movement and the work carrying tools a movement which isthe res sultant of a plurality of rectilinear move ments or vice-versa.

As illustrated the work carrying members comprise heads 6 having depending rods 7 provided with sphericalends 8 adapted to engage suitable sockets in the usual lens holders 9 having arms 10 terminating in a guide 11 received in a suitable guideway in an arm 12extending laterally from the head 6. The work carrying head 6 is rigidly clamped upon a slide preferably in the form of a cylindrical bar 13 which is slidably mounted in journals 14, 15 in a bracket 16 having a, preferably cylindrical clamping member 17 by which said bracket is secured to a cross head which desirably is a tube 18 extending transversely of the machine. The slide 13 desirably has upon it a collar 19 provided at one side with an upwardly extending boss 20 presenting a curved surface through which pressure is applied to the slide and therefore to the head to cause the head properly-to co-operatewith the grinding tool. The :pressure applying -means ger 22 is slidably mounted. A helical spring 23 surrounds said plunger and abuts at one end against a shoulder upon the same and is inclosed within said cylindrical boss and abuts at its opposite end against the end of an adjusting screw 24 which is seated in the free end of the cylindrical boss.

Any desirable means may be provided for transmitting pressure from the plunger to the collar 19. A desirable instrumentality which is illustrated herein comprises a rocker 25 which is mounted on a pivot 26 in said bracket and is provided with surfaces 27 and 28 positioned at substantially right angles to each other and which engage respectively the end of the plunger and the curved upper surface of the boss which projects upwardly from the collar 19.

The transmitter desirably is so proportioned that when the work carrying member is raised the end of said member which engages the boss 20 will ride upon the fiat surface 29 of the side of the collar 19 and boss 20. i

For convenience in operation a dog 30 is pivotally mounted upon an arm 12 and is adapted to engage a lug 31 projecting from the journal 14 of the bracket 16. By reason of this construction the operator is enabled to raise the work carrying member sufficiently to remove it from the grinding tool and latch it in suspended position thereby enabling him to insert and replace the work with great facility, and to render such member inoperative while others are being used.

Treadle operated means which will hereinafter be described are alSO desirably employed for retracting the pressure producing plunger or plungers so that the operator can raise each of the work carrying members out of operative position without undue exertion. The tubular work supporting member is supported at its ends in tubular preferably split sockets 32 which are clamped upon said tubular member by screws 33 and have laterally extending cylindrical bosses 34 to serve as journals for eccentrics 35 formed upon parallel vertical shafts 36, suitable bushings 37 being interposed between said eccentrics and bosses. The shafts 36 are supported at their upper ends in journals 5, and at their lower ends'are journals 38 in bosses formed in the web 39 on the frame 2. Counterweights 40 desirably are secured to the shafts 36 to counterbalance the weight of the crosshead 18 and that of the work supporting members carried thereby.

One of the shafts 36 is provided with a bevelled gear 43 which meshes with a complementary bevelled gear 44 upon the driving shaft 45 which is journalled in a bearing 46 which for convenience in assembling is carried by a bracket 47 bolted to the end of the main frame. The shaft 45 desirably is rotated by a pulley 48 which is driven by a belt 49 passing over a pulley 5O desirably secured directly upon the shaft 51 of an electric motor 52 mounted upon suitable stands 53 in the base portion of the machine.

The belt 49 desirably is loosely mounted upon the pulleys 48 and and is forced into driving relation or released therefrom by a belt tightener preferably in the form of a pulley 54 mounted upon a stud shaft 55 in the end of an arm 56 of a bell crank lever which is pivotally mounted upon a shaft 57 extending across the base of the machine. The other arm 58 of the bell crank lever is connected by a link 59 to the central portion of a lever 60 which is pivotally mounted upon a shaft 61 extending across the base of the machine, the opposite end of said lever being connected to a treadle 62 which is provided with a latch 63 adapted when the treadle is depressed to an intermediate position to engage a lug upon the base 1 and thereby lock the treadle lever 60 in such position that the pulley 54 is removed from driving engagement with the belt 49. Connterbalancing means such as a weight 64 fixed upon the shaft 57 serves to tend normally to force the pulley 54 into driving engagement with the belt 49.

By reason of this construction an easy starting and stopping movement of the grinding mechanism is provided which will avoid all shocks and j ars which might arise if a clutch were used. It will be understood however that any suitable driving mecha-' nism may be employed within the meaning and scope of the claims.

The other co-operating vertical shaft 36, for actuating the crosshead 18 of the work carrying member, is also provided with an eccentric 35 but driven in unison with the driven vertical shaft 36.

As illustrated herein this is accomplished through a train of gearing comprising a gear 65 fixed upon the driven shaft 36 which meshes with a gear 67 carried by a stud 68 journalled in a central boss 69 in the web 39, the gear 67 meshing with a gear 70 upon the other vertical shaft 36, the gears 65 and 70 being of the same pitch diameter to cause the vertical shafts 36 to rotate in unison.

The mechanism for actuating the grinding tools preferably is actuated through the shaft 68 so that a definite and certain co-ordination is always maintained between the movement of the grinding tool or tools and the work carrying member or members. The grinding tool or tools may be of any desired construction. As illustrated herein they are in the form of iron or steel tools 71 presenting curved grinding faces 72 conforming to the curvature of the lens or other work to be ground. The lower ends of said tools have sockets which are removably seated on pins 73 on the base 74 of a tool carrier, preferably in the form of a pan 75. A ll-shaped guiding rib 76 projecting downwardly from the bottom of the pan is seated in. a groove 77 in the upper face of a slide 78 thereby providing means for guiding the pan in a rec tilinear path upon said slide 78. If desired two or more of such ribs and grooves may be provided but preferably the opposite side of the tool carrier is provided with a flat rib 79 which rests upon a complementary flat surface 80 upon the slide. The slide 78 likewise is provided with one or more downwardly extending ribs 81 which engage a complementary groove or grooves in transverse ribs projecting upwardly from the frame 2. The guides 81 and complementary grooves for the slide 78 are disposed in angular relation to the guide 7 6 and groove 77 for the carriage 7 5, preferably the guides 81 being normal to the guides 76 so that the carriage 75 has a movement at right angles to that of the slide 78. A central plate 82 extends at right angles to the guides 81 and is provided with a' journal for a shaft hav ing an eccentric which actuates the tool carriage 75 as will hereinafter more fully appear.

Any suitable means may be provided for actuating the slide and carrier for the grinding tool in timed relation to each other and to the movement of the work carriers, but preferably a Wide difference in the cycle of movements of the work carriers, the tool carriers, and the slide is provided, which has been found very satisfactory. In actual practice three and one fifth rotations of the Work carrying heads to one complete longi tudinal movement of the tool carriage with seventeen and twenty-nine hundredths rotations of the work carrying heads to one transverse movement of the tool holder, but it will be readily understood that by varying the diameter of the driving gears, any other desired relation may be established between the movement of these parts to produce a fractional relation of movements which will cause each point in the grinding tool to traverse an extended path of several hundred feet upon the work before the completing of the cycle of its movement. By the present in vention the successive curvilinear, substantially parallel, portions of path of each ef fective grinding point are quite widely spaced apart so that the shifting of the ab rasive during the grinding operation will not cause the regrinding of a previously traced line, but all of the surface between the successive parallel portion of said path is traversed by said point before its cycle is completed.

Upon the upper end of the shaft 68 is an eccentric 83 which engages a crosshead or slide 84 mounted in a guideway 85 formed by parallel ribs extending downwardly from the central lower portion of the slide 78,

which desirably is made hollow orof Skeleton form.

The eccentric 83 desirably is formed upon a sleeve which ismoun-ted upon the shaft 68, the lower portion of said sleeve being milled to form a gear 87 whichis connected to and driven from the hub of the gear 67, the gear 67 and the combined gear and sleeve 87 being therefore rotatably mounted upon the shaft 68. The gear 87 engages and drives a 88 which is secured to the lower portion of a shaft 89 which is mounted in a boss 90 upon the central plate 82 which is fixedly mounted on the frame 2. The boss 89 extends through an aperture. 91 in the slide and is provided with an annular shoulder or collar 92 which rests upon the upper end of the boss 90 thereby supporting the shaft 89 and its gear 88 which may be secured upon the lower end of the it shaft byany suitable nut or collar 93, The shaft 89 is provided at its upper end with a preferably integral cylindrical extension 94, the axis of which is eccentric to theaxis of the shaft 89. An eccentric 95 is rotatably mounted upon the extension 95L of the shaft 89 and is adjustably clamped thereon by a collar 96 which is slidably secured uponthe extension 94 by a spline or feather 97. A nut 98 upon the extension 94 of the shaft 89 serves to force the collar 96 into engagement with the eccentric 95 and to clainp the same firmly between said collar andthe collar 92. The eccentric 95 engages and operates a slide'99 mounted in waysiin an extension .100 projecting laterally from the tool carriage 75.

The eccentric 95 may be provided at its upper end with an annular graduated dial 1010f the samediameter as that ofthe'coL lar 96, the latter being provided with an index 102 adapted to co-operate with the graduations 103 of the dial so that adjustment of the eccentric may be quickly and accurately determined.

Preferably the eccentric 95. is so constructed that it may be positioned to form a prolongation of the shaft 89, in which case no movement will be imparted to the carriage 7 5 by the rotation of the shaft 89, or a by adjustment of said eccentric any amplitude of movement may be imparted to the carriage within the range of thoeccentric. By reason of this construction the amplitude of movement of the carriage 75 may be readily adjusted to the character of the material being treated so that the most efficient grinding conditions may be maintained.

Adjustablemeans may also be provided if desired for varying the amplitude of move ment of the slide 78 but ordinarly this is not desirable or essential.

In the operation of the machine themovements imparted to the grinding tools are such that each point upon the grindingtool travels a path which is a resultant of the combined rectilinear. reciprocating movements, in angular relation to each other, of the tool carriage and the slide, moving at dilferent rates of speed. In the meantime the work is given a circular rotation, and the co-ordinated movements of the work carriers and the tools are such that each point on the grinding tool passes in successive separated loops over substantially every point upon the surface of the work in completing its cycle of operation without retracing its path or thereby producing a uniform surface of the desired character without scratches or uneven portions such as are produced in grinding machines of the usual character.

It has been found in practice that lenses ground upon the. grinding machine illustrated in the accompanying drawing have at the end of the grinding operation, and before polishing, a surface which is very nearly perfect so that the polishing of the surface is accomplished in much less timethan in any other machine heretofore employed.

In order to provide convenient means forreleasing the pressure between. the work carrying members and the grindmg members or tools, so that the operator may use his hands freely to insert and remove the work, or to examine the same,

means have been provided whereby pressure upon the tools may be released by depressing the treadle which. controls the driving mechanism, beyond the position which is required to release the belt tightener from driving relation tothe belt 49. In the preferred embodiment of the invention disclosed herein this is accomplished by a lever 104 pivotally mounted upon a stud 105 in each of the tool supporting brackets 16, one end of each lever engages the end of the plunger 22, the opposite end of said lever 104 extends over a rod 106 which extends lengthwise'of the machine and is secured at its end to an arm 107 of a bell crank lever 108 which is pivotally mounted on studs 109 projecting from brackets 110 secured to and extending upwardly from the upperends of the posts 4. The other arm 111 of the bell crank lever is pivotally connected to a screw threaded sleeve 112 into which a rod 113 is screwed, the lower end of the rod 113 having screw threaded engagement with a socket 114 in a link 115 provided with a slot 116 adapted to receive a pin 117 extending laterally from the end of an arm 118 adj ustably secured up on the shaft 57 upon which the bell crank lever of the belt tightener is also secured.

The arm 118 may be so fixed upon the shaft 57 by a set screw 119 that the stud 117 will not engage the upper end of the slot 116 until the treadle has been pressed below the position in which it is located by engagement of the latch 63 with the lug 64,

In operating the machine therefore the operator. steps upon and releases the latch 63 whereupon the counterweight 64 rocks the shaft 57 and the bell crank lever which carries the belt tightener pulley 54 so that the latter presses against the belt 49 with suflicient force to start and effect the driving of the machine' When it is desired to stop the machine the operator depresses the treadle 62 without step-ping upon the latch 63 until the latch engages the lug and locks the treadle in depressed position. In order to release the pressure upon the work he may depress the treadle still further, thereby causing the stud 117 in the end of the arm 118 to engage the upper wall of the slot 116 thereby forcing the rod 113 upwardly and rocking the rock shaft 108 about its pivot 109 so that the rod 106 will engage the levers 104 and raising their outer ends will cause their inner ends to force back the plungers 22. When the pressure is thus released the operator may grasp the bracket 12 of any Work carrier and easily raise the same until the latch 30 engages the lug 31 of the bracket 14. He may then remove the work for examination or replacement. Upon release of the pressure of his foot the treadle will be raised until the latch 63 engages the lug upon the base. As the Work carried by the different work carriers is examined thework carriers may be returned to operative position and the machine started by again releasing the latch 63 so that any one or any part of the work carriers may be placed in operative A It will be understood that the embodiment of the invention disclosed herein is of an illustratlve character and is not restrictive and that various modifications of construction. design and operation of parts may be made within the spirit and scope of the following claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is;

1. In a grinding machine comprising a grinding member and a work carrying member, means for moving one of said members bodily in. a circular path, a carriage supporting the other member, a slide supporting said carriage and means for imparting independent movements in different directions in parallel planes to said carriage and said slide.

2, In a grinding machine comprising a grinding member and a Work carrying member, means for moving one of said members bodily in a circular path. a arriage supporting the other member, a slide supporting said. carriage, means for reciprocating said carriage and slide in directions at right angles to each other and means for adjusting the amplitude of movement of said carriage.

3. In a grinding machine comprising a grinding member and a co-operating WOI'k carrying member, means for moving one of said members bodily in a circular path, a carriage supporting the other of said members, a slide supporting said carriage and means for reciprocating said slide, means including an eccentric for reciprocating said carriage on said slide in a different direction from the movement of reciprocation of said slide, and means for adjusting the position of the eccentric to vary the amplitude of movement of said carriage.

4}. In a grinding machine comprising a grinding member and a cooperating Work carrying member, means for moving one of said members bodily in a circular path, a slide, aicarriage supporting the other of said members slidably mounted on said slide to reciprocate in a different direction from the direction of reciprocation of said slide, means for reciprocating said slide, means for reciprocating said carriage including a rotatable shaft having an eccentric extension, and an eccentric adjustably mounted upon said extension and slidable means engaging said eccentric and said carrlage.

5. In a grinding machine comprising a relatively movable grinding too-l and a cooperating ork carrying member, a cross head, a sliding member mounted on said cross head supporting said Work carrying member, a spring actuated pressure applying means, means for transmitting the pressure of said pressure applying means to said sliding member, means for Withdrawing said pressure applying means Without separating the ork from engagement, with the grinding member, whereby the work carrying member may be removed from operative relation to the grinding tool, and means for locking said WOI'k carrying memher out of operative relation to said grinding tool whereby the work may be conveniently attached to and removed from said work carrying member.

6. In a. grmding machine comprising a relatively movable grinding tool and a cooperating Work carrying member, a cross head having a bracket thereon, a sliding member mounted in said bracket supporting said Work carrying member a spring actuated plunger mounted in said bracket. a transmitting member engaging said plunger and said sliding member acting to force said work carrying member toward said grinding tool and means for retracting said plunger to permit the work carrying member to be removed from operative relation to said tool.

7. In a grinding machine comprising a relatively movable grinding tool and a cooperating Work carrying member, a cross head having a bracket thereon, a sliding member mounted in said bracket supporting said work carrying member, aspring actuated plunger mounted in said bracket. a transmitting member engaging said plunger and said sliding member acting to force said Work carrying member toward said grinding tool, means for retracting said plunger to permit the Work carrying member to be removed from operative relation to said tool, and latching means upon said sliding member and said bracket for locking the Work carrying member out of operative relation to said grinding tool.

7 8. A grinding machine comprising a frame, vertical shafts mounted therein, eccentrics' on said shafts, a cross head mounted on said eccentrics and movable thereby in a circular path, Work carrying members supported on said cross head, a carriage having grinding tools disposed in cooperative relation to said Work carrying members and coordinated means for rotating said vertical shafts and for reciprocating said carriage.

9. A grinding machine comprising a frame, vertical shafts mounted therein, eccentrics on said shafts, a cross head mounted on said eccentrics, Work carrying mem bers supported on said cross head, a carriage having grinding tools disposed in cooperative relation to said Work carrying members, a slide supporting said carriage and coordinated means for rotating said vertical shafts and independently moving said carriage and said slide,

10. A grinding machine comprising a frame, vertical shafts mounted therein, eccentrics on said shafts, a cross head mounted on said eccentrics, WOIk carrying members supported on said cross head, a carniage having grinding tools disposed in cooperative relation to said work carrying members, a slide supporting said carriage, shafts having respectively means for actuating said carriage and said slide, and means for simultaneously rotating said vertical shafts and the shafts for actuating said carriage and said slide.

11. A grinding machine comprising a frame, vertical shafts mounted therein. 6v centrics on said shafts. a cross head mounted on said eccentrics, Work carrying members supported on said cross head, a carriage having rinding tools disposed in cooperative relation to said Work carrving members, a slide supporting said carriage, shafts having respectively means for actuating said carriage and said slide, means for simultanetraverse an extended course during its cycle of movement upon the work.

12. A grinding machine con'iprising a frame and bed, vertical shafts mounted therein, eccentrics on said shafts, a cross head mounted on said eccentrics, work carrying members supported on said cross head, a slide reciprocably mounted on said bed, a carriage mounted on said slide reciprocable in a direction normalto the direction of movement of said. slide, means including shafts having eccentrics for actuating said slide and said carriage, means for driving one of said vertical shafts, and a train of gears operated from one of said vertical shafts for driving the actuating shafts for said slide and carriage.

13. A grinding machine comprising a frame and bed, vertical shafts mounted therein, eccentrics on said shafts, a cross head mounted on said eccentrics, work carrying members supported on said cross head, a slide reciprocably mounted on said bed, a carriage mounted on said slide reciprocable in a direction normal to the direction of movement of said slide, means including shafts having eccentrics for actuating said slide and said carriage, means for driving one of said vertical shafts and a train of gears operated from one of said vertical shafts for driving the actuating shafts for said slide and carriage, the gears for said carriage actuating shaft and said slide actuating shaft being of different pitch diameters.

14. A grinding machine comprising a frame and bed, vertical shafts mounted therein, eccentrics on said shafts, a cross head mounted on said eccentrics, work carrying members supported on said cross head, a slide reciprocably mounted on said bed, a carriage mounted on said slide reciprocable in a direction normal to the direction of movement of said slide, a shaft located centrally between said vertical shafts having means for reciprocating said slide, means for driving one of said vertical shafts and a train of gears operated from the driven vertical shaft for rotating said centrally located shaft.

15. A grinding machine comprising a frame and bed, vertical shafts mounted therein, eccentrics on said shafts, a cross head mountedv on said eccentrics, work carrying members supported on said cross head, a slide reciprocably mounted on said bed, a carriage mounted on said slide reciprocable in a direction normal to the direction of movement of said slide, a shaft located centrallly between said vertical shafts having means for reciprocating said slide, means for driving one of said verticalshafts and a train of gears operated from the driven vertical shaft for rotating said centrally located shaft, a shaft having means for ac tuating said carriage, and means for driving said carriage actuating shaft from said centrally located shaft at a different speed of rotation than that of said centrally lo cated shaft.

16. In a grinding machine comprising a grinding member and a work supporting member, means for actuating said members and yieldablepressure applying means act ing normally to force said members into grinding relation, and manually controlled means for withdrawing said pressure applying means without removing said members from grinding relation or varying the adjustment of said pressure applying means.

17. In a grinding machine comprising a grinding member and a work supporting member, means for actuating said members and spring actuated pressure applying means acting normally to force said members into grinding relation, and manually controlled means operable when moved in one direction to render the actuating mechanism operative and when moved in the opposite direction to release said pressure applying means without removing said members from grinding relation whereby said members may be separated to permit insertion and removal of the work.

18 In a grinding machine comprising a grinding member and a work supporting member, means for actuating said members and yieldable pressure applying means acting normally to force said members into grinding relation, yieldable means tending normally to cause the operation of said actuating means, manually controlled means operable upon partial movement to release said actuating means and means operable upon further movement of said manually controlled means to release said pressure applying means whereby said members may be separated to permit insertion and removal of the work.

19. In a grinding machine comprising a, grinding member and a work supporting member, means for actuating said members and yieldable pressure applying means acting normally to force said members into grinding relation, treadle mechanism including counterbalancing means acting normally to raise the treadle and to render the actuating mechanism operative, means for looking the treadle when partially depressed to render the actuating means ineffective and means operable upon further depression of said treadle to release said pressure applying means whereby said members may be separated to permit insertion and removal of the Work.

20. In a grmding machine comprising a grinding member, a work carrying member and yieldable pressure applying means acting normally to force said member into grinding relation, actuating means for imparting relative grinding movement to said members including pulleys, a normally loose belt passing over said pulleys and a counterbalanced belt tightener tending normally to render said actuating means. operative, a treadle connected to said belt tightener adapted when partially depressed to render said belt tightener ineflective, and means operable upon further depression of said treadle to release said pressure applying means 2L In a grinding machine comprising a plurality of grinding. members and a plurality of: cooperating Work carryingmembers independently yieldable pressure applying means acting normally to force each of said work carrying members into grinding relation to its cooperating grinding member,

driving means for imparting a relative grinding movement to said members including pulleys, a normally loose belt passing over said pulleys, a counter-balanced rock shaft having a bell crank lever thereon. a belt tightening pulley sup-ported by one arm of said bell crank lever and normally forced. by said counter shaft into opera-ting engagement with said belt, a tread'le connected with the other arm of said bell crank lever, an arm on said rock shaft and means connected to said arm] for simultaneously re leasing said pressure applying means upon depression of the treadle below a predetermined position.

In testimony whereof, I have signed my name to this specification. U

WARREN F. FRASER. 

